A post hole digger attaches to the standard three point hitch of the tractor is powered by the tractor's power take-off (PTO). The digger comprises an auger without protrusions or other extending parts above the fighting of the auger, to reduce the possibility of a user becoming ensnared during use of the digger.
A gearbox translates rotation from the PTO shaft to the auger. In a traditional post hole digger, the auger's shaft attaches to the gearbox via a cross bolt that extends perpendicularly through the shaft. The cross bolt has the disadvantage of protruding from the shaft, and causing potential harm to a user. The digger of the present disclosure removes this disadvantage by providing a threaded fitting between the shaft and the gearbox. However, a threaded fitting on the rotating shaft provides an additional challenge When the auger needs to be removed from the gearbox.
The gearbox lock mechanism of the present disclosure comprises a collar coupled to a lower end of the gearbox, the collar rotatable upon operation of the gearbox. The collar comprises a semi-circular outer edge and a flat side. A male-threaded nipple extends from the collar and threads into the auger shaft. A lock bar is coupled to the gearbox and acts as a positive lock to lock the collar in place for removal of the shaft from the gearbox. The lock bar is rotatable from a locked position whereby the lock bar is aligned with and contactable with the flat side of the outer edge of the collar, to an unlocked position whereby the lock bar does not contact the flat side of the outer edge of the collar.
For purposes of summarizing the invention, certain aspects, advantages, and novel features of the invention have been described herein. It is to be understood that not necessarily all such advantages may be achieved in accordance with any one particular embodiment of the invention. Thus, the invention may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other advantages as may be taught or suggested herein.